Fix whoosh result sorting.

Now results are sorted by is-this-your-language (times levenshtein
distance, if appropriate), then by rough class of result (Pokémon, then
moves, then abilities, etc.) and finally by name.

This fixes a couple issues:

- If both a foreign name and a local name matched a wildcard lookup,
  you'll see the local name.  Before, you'd see whichever happened to be
  first alphabetically.

- Wildcard results are more likely to have useful stuff at the top,
  rather than being dominated by foreign junk and names of obscure
  locations.

This also updates our usage of the whoosh API, which was old and busted
as of 2.0 or so.

pokedex/lookup.py

@@ -12,6 +12,7 @@ import whoosh.filedb.fileindex
 import whoosh.index
 from whoosh.qparser import QueryParser
 import whoosh.scoring
+import whoosh.sorting
 import whoosh.spelling
 from whoosh.support import levenshtein
 
@@ -49,40 +50,51 @@ class UninitializedIndex(object):
             "or lookup.rebuild_index() to create it."
         )
 
-class LanguageWeighting(whoosh.scoring.Weighting):
-    """A scoring class that forces otherwise-equal English results to come
-    before foreign results.
+def LanguageFacet(locale_ident, extra_weights={}):
+    """Constructs a sorting function that bubbles results from the current
+    locale (given by `locale_ident`) to the top of the list.
+
+    `extra_weights` may be a dictionary of weights which will be factored in.
+    Intended for use with spelling corrections, which come along with their own
+    weightings.
     """
-
-    def __init__(self, locale_ident, extra_weights={}, *args, **kwargs):
-        """`extra_weights` may be a dictionary of weights which will be
-        factored in.
-
-        Intended for use with spelling corrections, which come along with their
-        own weightings.
-        """
-        self.locale_ident = locale_ident
-        self.extra_weights = extra_weights
-        super(LanguageWeighting, self).__init__(*args, **kwargs)
-
-    def score(self, searcher, fieldnum, text, docnum, weight, QTF=1):
+    def score(searcher, docnum):
         doc = searcher.stored_fields(docnum)
+        weight = extra_weights.get(doc['name'], 1.0)
 
-        # Apply extra weight
-        weight = weight * self.extra_weights.get(text, 1.0)
-
-        doc_language = doc.get('language')
-
-        if doc_language == self.locale_ident:
+        doc_language = doc['language']
+        if doc_language == locale_ident:
             # Bump up names in the current locale
-            return weight * 2.0
+            weight *= 2.0
         elif doc_language == u'roomaji':
             # Given that the Japanese names are the originals, it seems likely
             # that basically anyone might want to look them up.  Boost them a
             # little bit.
-            return weight * 1.4
+            weight *= 1.4
 
-        return weight
+        # Higher weights should come FIRST, but sorts are ascending.  Negate
+        # the weight to fix this
+        return -weight
+
+    return whoosh.sorting.FunctionFacet(score)
+
+_table_order = dict(
+    pokemon_species=1,
+    pokemon_forms=1,
+    moves=2,
+    abilities=3,
+    items=4,
+    types=5,
+    locations=6,
+    natures=7,
+)
+def _table_facet_impl(searcher, docnum):
+    u"""Implements a sort that puts different "types" of results in a
+    relatively natural order: Pokémon first, then moves, etc.
+    """
+    doc = searcher.stored_fields(docnum)
+    return _table_order[doc['table']]
+table_facet = whoosh.sorting.FunctionFacet(_table_facet_impl)
 
 
 class PokedexLookup(object):
@@ -468,21 +480,22 @@ class PokedexLookup(object):
         # Fuzzy are capped at 10, beyond which something is probably very
         # wrong.  Exact matches -- that is, wildcards and ids -- are far less
         # constrained.
-        # Also, exact matches are sorted by name, since weight doesn't matter.
-        sort_by = dict()
         if exact_only:
             max_results = self.MAX_EXACT_RESULTS
-            sort_by['sortedby'] = (u'table', u'name')
         else:
             max_results = self.MAX_FUZZY_RESULTS
 
         locale = self._get_current_locale()
-        searcher = self.index.searcher(
-            weighting=LanguageWeighting(locale.identifier))
+        facet = whoosh.sorting.MultiFacet([
+            LanguageFacet(locale.identifier),
+            table_facet,
+            "name",
+        ])
+        searcher = self.index.searcher()
         results = searcher.search(
             query,
             limit=int(max_results * self.INTERMEDIATE_FACTOR),
-            **sort_by
+            sortedby=facet,
         )
 
         # Look for some fuzzy matches if necessary
@@ -492,10 +505,8 @@ class PokedexLookup(object):
 
             fuzzy_query_parts = []
             fuzzy_weights = {}
-            min_weight = [None]
             corrector = searcher.corrector('name')
             for suggestion in corrector.suggest(name, limit=max_results):
-
                 fuzzy_query_parts.append(whoosh.query.Term('name', suggestion))
                 distance = levenshtein.relative(name, suggestion)
                 fuzzy_weights[suggestion] = distance
@@ -508,9 +519,9 @@ class PokedexLookup(object):
             if type_term:
                 fuzzy_query = fuzzy_query & type_term
 
-            searcher.weighting = LanguageWeighting(
+            sorter = LanguageFacet(
                 locale.identifier, extra_weights=fuzzy_weights)
-            results = searcher.search(fuzzy_query)
+            results = searcher.search(fuzzy_query, sortedby=sorter)
 
         ### Convert results to db objects
         objects = self._whoosh_records_to_results(results, exact=exact)
@@ -570,7 +581,7 @@ class PokedexLookup(object):
 
         locale = self._get_current_locale()
         searcher = self.index.searcher()
-        searcher.weighting = LanguageWeighting(locale.identifier)
-        results = searcher.search(query)  # XXX , limit=self.MAX_LOOKUP_RESULTS)
+        facet = LanguageFacet(locale.identifier)
+        results = searcher.search(query, sortedby=facet)  # XXX , limit=self.MAX_LOOKUP_RESULTS)
 
         return self._whoosh_records_to_results(results)